DE102021002942A1 - Process for producing a permanent magnet for an electrical machine, permanent magnet and use of a permanent magnet - Google Patents

Abstract

The invention relates to a method for producing at least one permanent magnet (10a-d) for an electrical machine. A permanent magnetic body (12) is manufactured by compression molding or extrusion. A first portion (16a-d) of the base body (12) is separated from at least a second portion (18) of the base body by a cutting process, with at least one permanent magnet (10a-d) being provided by the first portion (16a-d). The at least one permanent magnet (10a-d) is provided with a recess (14a-d) by the cutting process.

Description

The invention relates to a method for producing at least one permanent magnet for an electrical machine, in particular a motor vehicle. The invention also relates to a permanent magnet for an electrical machine. Furthermore, the invention relates to the use of a permanent magnet.

the DE 100 27 086 A1 discloses a magnetic element cutting method, with a first step of preparing a cutting blade having a cutting edge comprising abrasive grain and a heat-resistant resin. The magnetic element cutting method includes a second step of cutting a magnetic element by the cutting blade while supplying a temperature-controlled coolant to a cutting region. From the DE 101 57 433 A1 a method of cutting a rare earth metal alloy using a wire with abrasive grains is known. In addition, the WO 03/074229 A1 a method of cutting a rare earth metal alloy. In addition, from the DE 10 2017 200 142 A1 a segmented magnet is known.

The object of the present invention is to create a method for producing at least one permanent magnet for an electrical machine, in particular a motor vehicle, a permanent magnet for an electrical machine, in particular a motor vehicle, and the use of a permanent magnet, so that the permanent magnet can be produced particularly quickly and cost-effectively can be made.

This object is achieved by a method having the features of patent claim 1, by a permanent magnet having the features of patent claim 9 and by a use having the features of patent claim 10.

Advantageous configurations with expedient developments of the invention are specified in the remaining claims.

A first aspect of the invention relates to a method for producing at least one permanent magnet for an electrical machine, in particular a motor vehicle. This means that the motor vehicle, which is preferably designed as a motor vehicle, in particular as a passenger car, has the electrical machine in its fully manufactured state and can be driven electrically, in particular purely electrically, by means of the electrical machine. Thus, the motor vehicle is preferably a hybrid or electric vehicle, in particular a battery electric vehicle (BEV). The electrical machine is preferably designed as a high-voltage component whose electrical voltage, in particular electrical operating or nominal voltage, is preferably greater than 50 volts, in particular greater than 60 volts, and very preferably amounts to several hundred volts. As a result, particularly high electrical power can be realized for, in particular, purely electrical driving of the motor vehicle. The electrical machine is preferably an axial flow machine which has an axial air gap. This is to be understood in particular as follows: The axial flux machine has a stator and at least one rotor which can be rotated about an axis of rotation relative to the stator. An air gap is arranged between the stator and the rotor, the air gap being arranged between the stator and the rotor in the axial direction of the axial flow machine, that is to say viewed along the axis of rotation. In other words, the stator and the rotor are arranged next to one another or one after the other in the axial direction of the axial flow machine. In particular, the axial flow machine can have a double rotor, that is to say two rotors which are preferably arranged coaxially to one another. The rotors are rotatable about the axis of rotation relative to the stator. In this case, the stator is arranged, for example, in the axial direction of the axial flux machine between the rotors, in particular in such a way that an air gap is arranged in the axial direction of the axial flux machine between the stator and the respective rotor. In particular, the axial flow machine can provide torque for driving the motor vehicle via its rotor.

In a first step of the method, a permanent magnetic base body, ie a permanent magnetic base body, is produced by compression molding or extrusion. In other words, in the first step of the process, a compression molding process or an extrusion molding process is carried out, with the permanent magnetic base body being produced by means of the compression molding process or by means of the extrusion molding process. In particular, the permanently magnetic (permanently magnetic) base body is produced from a molding compound which is processed during compression molding or extrusion, that is to say it is pressed. The molding compound is preferably a molten material, ie a melt of a material from which the base body is produced. The molding compound or the melt is shaped by compression molding or extrusion. The molding compound can have a plastic and permanently magnetic or permanently magnetic particles embedded in the plastic, or the material or the molding compound itself is permanently magnetic. By means of compression molding or extrusion pressing, the base body can be produced in a particularly time- and cost-effective manner.

In a second step of the method that preferably follows the first step of the method, a first partial area of the base body is separated, in particular at least or precisely, from at least a second partial area of the base body by a cutting method, in particular by jet cutting, i. H. separated. In other words, a cutting method, in particular a jet cutting method, is carried out in the second step of the method. In the case of jet cutting or in the case of the jet cutting method, at least or precisely a cutting jet, also simply referred to as a jet, is provided, by means of which the first partial area is separated or severed from the second partial area of the base body. For example, the cutting beam is applied to the base body and in other words the base body is exposed to the cutting beam in such a way that the first partial area is separated from the second partial area by means of the cutting jet, i. H. is cut off. The cutting beam can, for example, be an energy beam, in particular an electron beam or a laser beam. However, it has proven to be particularly advantageous if the cutting jet is a fluid jet, ie formed by a fluid such as a liquid. In particular, the cutting jet is provided along a jet direction, for example by a cutting tool also referred to as a tool, in particular in such a way that the cutting jet impinges on the base body along the jet direction or that the base body is acted upon by the cutting jet along the jet direction. For example, the cutting beam is moved along a separating or cutting direction relative to the base body. For example, the separation direction runs in one plane, it being conceivable for the beam direction to run at an angle or perpendicular to the plane. In the second step of the method, the at least one permanent magnet is provided by the first partial area. In other words, the first portion is used as the at least one permanent magnet. Expressed again in other words, the at least one permanent magnet is produced in that the first partial area, which forms or provides the at least one permanent magnet, is separated from the second partial area. The first sub-area can be separated from the second sub-area particularly quickly and inexpensively by jet cutting, and a needs-based shape or geometry, in particular on the outer circumference, of the first sub-area and thus of the at least one permanent magnet can be produced in a particularly time-saving and cost-effective manner by jet cutting will.

In a third step of the method, the at least one permanent magnet, in particular a surface or an outer peripheral lateral surface of the at least one permanent magnet, is provided with, in particular at least or exactly, one, in particular continuous or uninterrupted, recess by the cutting process. The cutting method or the cutting beam is thus also used to cut the recess of the at least one permanent magnet, d. H. For example, to produce the recess in the surface or the outer peripheral lateral surface of the at least one permanent magnet. Since the cutting process is used both for separating the first partial area from the second partial area and for producing the recess, the at least one permanent magnet can be produced in a particularly time-saving and cost-effective manner and can therefore also be provided with the recess. Through the recess d. H. By producing the recess, eddy current losses can be kept particularly low, in particular during operation of the electric machine, so that particularly efficient operation can be achieved in a particularly cost-effective manner.

The invention is based in particular on the following findings: In order to be able to keep eddy current losses sufficiently low in magnets of electrical machines, axial flux machines, in particular designed as permanent magnets, thin, individual magnets are usually used. For example, the thin, individual magnets are stacked or arranged on top of one another as respective, individual, thin layers, and the stacked or arranged on top of one another, permanent magnetic layers are packaged, thus connected to one another, whereby a stable, permanent magnetic, ie permanent magnetic package can be created . The permanent magnetic package is used from permanent magnetic overall magnet. It is conceivable to equip the axial flux machine with several such permanent-magnetic packages. The packaging takes place, for example, in such a way that the individual, thin magnets, and therefore the layers, are connected to one another, therefore glued to one another, by means of an adhesive. A large number of process steps and thus a long process time are usually required for the production of the permanent-magnetic overall magnet, so that the permanent-magnetic overall magnets can only be produced in a very time-consuming and expensive manner. For example, the layers are individual sheets, ie formed from sheet metal, in particular electrical sheet metal, with the layers being connected to one another. This connection or the packaging of the layers is time-consuming and requires additional connections Technologies such as gluing, or an adhesive to connect the layers together. If, for example, an external peripheral shape that is different from a rectangular shape or from a cuboid shape, such as a trapezoidal shape of the overall magnet, is to be produced, then different layers, i.e. layers with different shapes, usually have to be stacked on top of one another, so that the layers themselves have to be produced in a very time-consuming and costly manner .

The problems and disadvantages mentioned above can now be avoided by the invention. On the one hand, the base body itself can be manufactured in a particularly time-saving and cost-effective manner. On the other hand, the first sub-area can be separated from the second sub-area in a particularly time- and cost-effective manner, with a desired outer peripheral shape of the at least one permanent magnet being able to be produced during the separation or during the separation, in particular at the same time. The shape of the permanent magnet and thus the permanent magnet as a whole can thus be produced in a particularly time-saving and cost-effective manner, since the permanent magnet can also be provided with the recess in a particularly time-saving and cost-effective manner using the cutting method.

In order to be able to produce the at least one permanent magnet particularly quickly and inexpensively, one embodiment of the invention provides for jet cutting, in particular water jet cutting, to be used as the cutting method. The cutting jet is thus preferably a water jet, which means it is formed at least predominantly, in particular exclusively, from water.

A further embodiment is characterized in that the separation of the first partial area from the second partial area and the provision of the at least one permanent magnet with the recess can be carried out in one go, i. H. be carried out without interruption. This means that the cutting process is not interrupted between the separation of the first partial area from the second partial area and the provision of the at least one permanent magnet with the recess. In other words, it is provided that between the separation of the first partial area from the second partial area and the provision of the at least one permanent magnet with the recess, the impingement of the cutting beam on the base body does not end. To put it another way: the cutting beam is provided in particular by the aforementioned tool and is applied or radiated in particular to the base body in order to separate the first partial area from the second partial area and to produce the recess, and therefore the at least one permanent magnet with the recess to provide. It is preferably provided that between the separation of the first sub-area from the second sub-area and the provision of the at least one permanent magnet with the recess, the provision of the cutting beam is not terminated, so that the cutting beam preferably starts from the beginning of the separation of the first sub-area from the second Section continuous up to one end of the provision of the at least one permanent magnet with the recess, d. H. provided without interruption and in particular continuously, d. H. uninterrupted on the base body, d. H. is radiated onto the first sub-area and/or the second sub-area. Thus, the separation of the first partial area from the second partial area and the provision of the at least one permanent magnet with the recess take place at least essentially continuously, i. H. in one and the same, in particular continuous, process, as a result of which the at least one permanent magnet can be produced in a particularly time-saving and cost-effective manner.

In a further, particularly advantageous embodiment of the invention, it is provided that the recess is produced as a blind hole. This means that the recess is not produced as a through opening that completely penetrates the at least one permanent magnet, but rather the recess is produced in such a way that, like a blind hole, it is not completely continuous along the beam direction, but along the beam direction through a remaining wall area of the at least one permanent magnet is limited.

Alternatively, it has proven to be advantageous if the recess is produced as a through-opening, in particular as a through-slot, which completely penetrates the at least one permanent magnet. As a result, eddy current losses in the at least one permanent magnet can be kept particularly low, and in a particularly cost-effective manner.

In order to be able to produce the permanent magnet in a particularly time- and cost-effective manner and to be able to keep eddy current losses particularly low, it is provided in a further embodiment of the invention that the recess runs in an arc, in particular in a meandering shape. This is to be understood in particular as meaning that the recess is arcuate, at least in one length region, in particular meandering, runs. It is conceivable that, for example, the recess is kinked at least in a second length area, in particular in such a way, and that, for example, a first part of the second length area and a second part of the second length area each run in a straight line, with the second part preferably adjoining the first part directly adjoins, and it is preferably provided that the first part and the second part enclose an angle different from 0 and 180° with one another, and therefore run obliquely or perpendicularly to one another. As a result, excessive eddy current losses can be avoided particularly well.

A further embodiment is characterized in that the at least one permanent magnet is produced triangularly, in particular on the outer circumference. As a result, a particularly advantageous shape of the permanent magnet, in particular on the outer circumference, can be produced in a particularly cost-effective and time-saving manner, as a result of which eddy current losses can be kept particularly low.

In a further, particularly advantageous embodiment of the invention, it is provided that the base body as a cuboid, i. H. is produced as a rectangular or cuboid block. As a result, the base body and thus the at least one permanent magnet as a whole can be produced in a particularly time-saving and cost-effective manner.

A further embodiment is characterized in that the base body is produced in a trapezoidal shape, in particular on the outer peripheral side. As a result, a particularly advantageous, outer peripheral shape of the at least one permanent magnet can be produced in a particularly time- and cost-effective manner, so that, for example, the at least one permanent magnet can be positively connected or is connected to a carrier of the electrical machine in a particularly simple and cost-effective manner.

Finally, it has been shown to be particularly advantageous if at least one form-fitting element of the at least one permanent magnet is produced, which can be positively connected or is connected to the carrier of the electrical machine by means of the form-fitting element. For example, the positive-locking element is produced by compression molding or by extrusion. Alternatively or additionally, the form-fitting element can be produced by the cutting process. The at least one permanent magnet can thus be provided with the form-fitting element in a particularly time-saving and cost-effective manner, so that additional subsequent process steps for producing the form-fitting element or a form-fitting element can be avoided. The positive-locking element can be used to connect the permanent magnet to the carrier in a particularly advantageous manner, and therefore to hold it on the carrier. Overall, the at least one permanent magnet can be produced in a particularly time-saving and cost-effective manner, so that the electrical machine can be produced in a particularly time-saving and cost-effective manner.

A second aspect of the invention relates to a permanent magnet for an electrical machine, in particular for an axial flux machine, the permanent magnet according to the second aspect of the invention being produced by means of a method according to the first aspect of the invention. Advantages and advantageous configurations of the first aspect of the invention are to be regarded as advantages and advantageous configurations of the second aspect of the invention and vice versa.

A third aspect of the invention relates to the use of a permanent magnet according to the second aspect of the invention, the permanent magnet being used for an electrical machine designed as an axial flux machine. Advantages and advantageous configurations of the first and second aspect of the invention are to be regarded as advantages and advantageous configurations of the third aspect of the invention and vice versa.

The permanent magnet is preferably used for a rotor or the rotor of the axial flux machine, so that when the axial flux machine is completely manufactured, the permanent magnet and preferably the aforementioned carrier are part or parts of the rotor of the axial flux machine.

• - kleinere Schnittlänge
• - geringere Anzahl an Prozessschritten
• - verringerte Prozesszeiten

Compared to conventional solutions, the following advantages in particular can be realized by the invention:

• - smaller cutting length
• - lower number of process steps
• - Reduced process times

Through the cutting process, a particularly advantageous and needs-based contour of the recess can be produced in a particularly time-saving and cost-effective manner. For example, the recess can extend in a serpentine or wavy manner at least in a longitudinal region of the recess, as a result of which eddy current losses can be kept particularly low.

It was found to be particularly advantageous if the second section of the base body pers a second permanent magnet is provided. In other words, it is conceivable that the second partial area of the base body is also used as a second permanent magnet for the electrical machine, in particular an axial flux machine. It has been shown to be particularly advantageous if, in the third step of the method, the second permanent magnet is also provided with at least or precisely one second recess by the cutting method. The previous and following statements relating to the at least one permanent magnet and the first recess can also be readily applied to the second permanent magnet and the second recess and vice versa. The method according to the invention thus makes it possible to produce a large number of permanent magnets for an electrical machine, in particular for an axial flow machine, in a particularly time-saving and cost-effective manner and in particular to provide them with the recesses, so that eddy current losses can be kept particularly low.

Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and from the drawing. The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and/or shown alone in the figures can be used not only in the combination specified in each case, but also in other combinations or on their own, without going beyond the scope of the leave invention.

• 1 eine schematische Darstellung eines ersten Teils eines Verfahrens zum Herstellen wenigstens eines Permanentmagneten gemäß einer ersten Ausführungsform für eine insbesondere als Axialflussmaschine ausgebildete, elektrische Maschine;
• 2 eine schematische Darstellung eines zweiten Teils des Verfahrens gemäß 1;
• 3 eine schematische Perspektivansicht des Permanentmagneten gemäß seiner zweiten Ausführungsform, bevor der Permanentmagnet mit einer Ausnehmung versehen wird;
• 4 eine schematische Perspektivansicht des mit der Ausnehmung versehenen Permanentmagneten gemäß der zweiten Ausführungsform;
• 5 eine schematische Draufsicht des Permanentmagneten gemäß seiner dritten Ausführungsform;
• 6 eine schematische und geschnittene Seitenansicht des Permanentmagneten gemäß 5;
• 7 eine schematische Draufsicht des Permanentmagneten gemäß seiner vierten Ausführungsform;
• 8 eine schematische und geschnittene Seitenansicht des Permanentmagneten gemäß der vierten Ausführungsform;
• 9 eine weitere schematische Draufsicht des Permanentmagneten gemäß der dritten Ausführungsform;
• 10 eine schematische Vorderansicht einer Matrize zum Strangpressen eines Grundkörpers zum Herstellen des Permanentmagneten;
• 11 eine schematische Vorderansicht des Grundkörpers, aus welchem der Permanentmagnet gemäß seiner fünften Ausführungsform hergestellt wird;
• 12 eine schematische Vorderansicht des Grundkörpers, aus welchem der Permanentmagnet gemäß seiner sechsten Ausführungsform hergestellt wird;
• 13 eine schematische Vorderansicht des Grundkörpers, aus welchem der Permanentmagnet gemäß einer sechsten Ausführungsform hergestellt wird; und
• 14 eine weitere schematische Vorderansicht des Grundkörpers, aus welchem der Permanentmagnet gemäß der fünften Ausführungsform hergestellt wird.

The drawing shows in:

• 1 a schematic representation of a first part of a method for producing at least one permanent magnet according to a first embodiment for an electrical machine designed in particular as an axial flux machine;
• 2 a schematic representation of a second part of the method according to 1 ;
• 3 a schematic perspective view of the permanent magnet according to its second embodiment, before the permanent magnet is provided with a recess;
• 4 12 is a schematic perspective view of the permanent magnet provided with the recess according to the second embodiment;
• 5 a schematic plan view of the permanent magnet according to its third embodiment;
• 6 a schematic and sectional side view of the permanent magnet according to 5 ;
• 7 a schematic plan view of the permanent magnet according to its fourth embodiment;
• 8th a schematic and sectional side view of the permanent magnet according to the fourth embodiment;
• 9 a further schematic plan view of the permanent magnet according to the third embodiment;
• 10 a schematic front view of a die for extrusion of a base body for producing the permanent magnet;
• 11 a schematic front view of the base body from which the permanent magnet is produced according to its fifth embodiment;
• 12 a schematic front view of the base body from which the permanent magnet is produced according to its sixth embodiment;
• 13 a schematic front view of the base body from which the permanent magnet is produced according to a sixth embodiment; and
• 14 a further schematic front view of the base body from which the permanent magnet is produced according to the fifth embodiment.

Elements that are the same or have the same function are provided with the same reference symbols in the figures.

Based on 1 and 2 a method for producing permanent magnets 10a-d according to a first embodiment for an electrical machine designed as an axial flux machine is described below. This means that the permanent magnets 10a-d, which are also referred to as permanent magnets, are used in the axial flux machine mentioned, ie in the fully manufactured state of the axial flux machine they are components of the axial flux machine. In particular, the permanent magnets 10a-d are used for a rotor of the axial flux machine, so that when the axial flux machine is completely manufactured, the permanent magnets 10a-d are components of the rotor of the axial flux machine.

• - Entfall von zusätzlichen Verbindungstechnologien
• - kleinere Schnittlänge
• - geringe Anzahl an Prozessschritten
• - verringerte Prozesszeit

In a first step S1 of the method, a permanent magnetic, ie permanent magnetic base body 12 by compression molding or preferably made by extrusion. The permanent magnetic base body 12 is in 1 shown in a schematic top view labeled A1 and in a schematic side view labeled A2. It can be seen that in the first embodiment the permanent magnetic base body 12 is produced as a rectangular or cuboid, in particular solid, block by compression molding or preferably by extrusion. 1 also shows partial steps S2.1, S2.2 and S2.3 of a second step S2 of the method. In the second step S2 of the method, which follows in particular the first step S1, the base body 12 and thereby the permanent magnets 10a-d, which are produced from the preferably extruded, permanent magnetic base body 12, are also cut by a cutting method, presently designed as beam cutting recesses 14a-d referred to as contours or having a respective contour, in particular in such a way that the permanent magnetic base body 12 is provided with the recesses 14a-d in such a way that the permanent magnet 10a with the recess 14a, the permanent magnet 10b with the recess 14b, the permanent magnet 10c with the recess 14c and the permanent magnet 10d with the recess 14d, thus the respective permanent magnet 10a-d is provided with at least or exactly one of the respective recesses 14a-d. In a third step S3 of the method that follows, for example, the second step S2, respective sub-areas 16a-d of the base body 12 are separated from one another and preferably also from at least or exactly one further sub-area or from several further sub-areas of the base body 12 by jet cutting, the permanent magnets 10a-d being provided by the partial areas 16a-d, such that the permanent magnet 10a is provided by the partial area 16a, the permanent magnet 10b by the partial area 16b, the permanent magnet 10c by the partial area 16c and the permanent magnet 10d by the partial area 16d becomes. In other words, the partial areas 16a-d of the base body 12 are used as the permanent magnets 10a-d. In particular, it is provided in the third step S3 that the partial areas 16a-d and thus the permanent magnets 10a-d are cut into shape by the beam cutting and in particular are produced or provided with a shape or contour or geometry on the outer circumference. The respective further partial area of the base body 12 is also referred to as a waste and is 2 denoted by 18, so that the partial areas 16a-d are separated from one another and from the waste by the jet cutting, ie are separated. In the fully manufactured state of the permanent magnets 10a-d, which are also referred to simply as magnets, the magnets are individual magnets, and therefore components that are constructed separately from one another, and in the fully manufactured state of the permanent magnets 10a-d, the permanent magnets 10a-d have the recesses 14a- d on. The respective, fully manufactured permanent magnet 10a-d is therefore a beam-cut and extruded magnet, which means that the following advantages in particular can be realized:

• - Elimination of additional connection technologies
• - smaller cutting length
• - low number of process steps
• - reduced process time

The permanent magnets 10a-d can thus be produced in a particularly time-saving and cost-effective manner. By providing the permanent magnets 10a-d with the recesses 14a-d, eddy current losses in the permanent magnets 10a-d can also be kept particularly low.

The jet cutting is advantageously carried out with an optimized cutting length. It has also been shown to be particularly advantageous if water jet cutting is used as the jet cutting. In the case of beam cutting, it is provided in particular that a cutting tool, also referred to as a tool, for example, provides a cutting beam, also referred to as a beam, and therefore emits it, in particular along a beam direction. The cutting jet is preferably made of a liquid that contains at least water, for example, and is therefore designed as a liquid jet, in particular as a water jet is radiated onto the respective partial area 16a-d and/or 18. Expressed again in other words, for example when the recess 14a-d is produced and when the partial regions 16a-d are separated, the base body 12 is acted upon by the cutting beam, in particular along the beam direction.

It is preferably provided that the separation of the partial areas 16a-d from one another and from the respective further partial area 18 and the provision of the base body 12 and thus the permanent magnets 10a-d with the recesses 14a-d are carried out in one go, i.e. without interruption, so that between the separation of the partial areas 16a-d from each other and from the respective partial area 18 and the provision of the base body 12 with the recesses 14a-d an interruption of the jet cutting, ie an end the cutting beam is not provided by the tool.

Particularly good looking 1 and 2 it can be seen that it is preferably provided that the respective recess 14a-d runs at least essentially in a meandering manner. The respective recess 14a-d is a recess of a respective surface 20 or of a respective lateral surface of the respective permanent magnet 10a-d on the outer circumference. Besides, it's off 2 recognizable that the respective permanent magnet 10a-d is made triangular, ie has a triangular shape in its fully manufactured state. At the in 1 and 2 In the exemplary embodiment shown, it is provided that the respective permanent magnet 10a-d has the shape of a triangle, two sides of the triangle being straight and the third side of the triangle being arc-shaped, in particular arc-shaped.

3 shows the permanent magnetic base body 12, from which the 4 shown permanent magnet 10a is produced according to a second embodiment. The base body 12 is produced by extrusion, so that the base body 12 is an extruded profile, in particular a solid extruded profile. In particular, it is preferably provided that the base body 12 is formed in one piece. The base body 12 is provided with the recess 14a which, as shown in FIG 4 can be seen, runs meandering.

5 and 6 show a third embodiment of the permanent magnet 10a. Out of 5 and 6 It can be seen particularly well that the recess 14a is produced, for example, as a blind hole or in the manner of a blind hole, so that the recess 14a does not completely penetrate the permanent magnet 10a along the beam direction, but is limited by a wall region W of the permanent magnet 10a.

7 and 8th show a fourth embodiment of the permanent magnet 10a. In the fourth embodiment, the recess 14a is formed as a through hole or in the manner of a through hole that completely penetrates the permanent magnet 10a. Particularly good looking 5 until 8th it can be seen that the permanent magnet 10a is provided with exactly one recess 14a by the jet cutting, the recess 14a running continuously, ie without interruption. Thus, for example, to manufacture the third embodiment, the jet cutting is performed as a cutting process to form the recess 14a as a blind hole or in the manner of a blind hole. For manufacturing the fourth embodiment, the jet cutting is performed as a severing process, by means of which the recess 14a is formed as a through hole.

It is conceivable that as the cutting process, by means of which the partial areas 16a-d are separated from one another and from the waste and the permanent magnets 10a-d are provided with the recesses 14a-d, laser cutting, i. H. a laser cutting method is used, so that the cutting beam is an energy beam or a laser beam. Furthermore, it is conceivable that wire EDM is used as the cutting method. In particular, by using wire EDM as the cutting method, the cutting method can be carried out particularly advantageously as the severing method described above, as a result of which, for example, the recess 14a can be particularly advantageously produced as a through opening.

9 10 shows the permanent magnet 10a according to the third embodiment in a further, schematic plan view. It can be seen that the recess 14a can have at least or precisely two length regions running in a straight line, which run obliquely or perpendicularly to one another. Alternatively or additionally, the recess 14a can have arcuate, in particular meandering, longitudinal regions. In particular, the recess 14a is formed by at least or exactly one cutting line, which is produced by the cutting process. The cutting line can run horizontally in at least a first length range and/or run at an angle in at least a second length range. In other words, respective longitudinal areas of the recess 14a can be arranged at any desired angle, in particular with respect to one another. In 9 an angle is denoted by α, which is enclosed by a longitudinal region of the recess 14a, denoted by L and running at least essentially in a straight line, and an edge K of the base body 12, designed in particular as a cutting edge.

10 shows a schematic front view of a die 21, which is produced during the extrusion and thus for the extrusion of the base body 12. 11 shows a fifth embodiment of the base body 12, which by means of the die 21 according to 10 will be produced. The die 21 has an opening 22 through which a semi-finished product from which the base body 12 according 11 is produced, is pressed through. Out of 11 it can be seen that the base body 12 according to the fifth embodiment is trapezoidal, in particular in relation to its cross section.

12 shows a sixth embodiment of the base body 12. In the sixth Ausfüh ment shape, the base body 12 has form-fitting elements 24 and 26, with the permanent magnet 10, which is produced from the base body 12, preferably having the form-fitting elements 24 and 26 in its fully manufactured state. The respective positive-locking element 24 or 26 is, for example, a tongue and groove element, which can be arranged in a corresponding receptacle, embodied, for example, as a groove, of a carrier of the axial flow machine, such that the permanent magnet 10a can be positively connected to the carrier by means of the positive-locking elements 24 and 26. ie can be fastened to the carrier. The positive-locking elements 24 and 26 are produced, for example, by extrusion and/or by the cutting process.

13 shows the base body 12 according to a seventh embodiment. In the seventh embodiment, too, the base body 12 and the permanent magnet 10a, which is produced from the base body 12, have a positive-locking element 28, which can be designed as a tongue and groove element, for example. The previous and following statements on the respective form-fitting element 24 or 26 can also be transferred to the form-fitting element 28 and vice versa. In electrical machines, magnets are usually connected to a carrier, such as a rotor core of the rotor of the electrical machine, by means of adhesive connections. The adhesive connections and the magnets are exposed to high, critical temperatures and loads. The respective positive-locking element 24, 26 or 28 now makes it possible to connect the respective permanent magnet 10a-d not or not only materially to the carrier such as the rotor core, but rather the respective permanent magnet 10a-d can be connected by means of the respective positive-locking element 24, 26 or 28 can be positively connected to the carrier, which is designed in particular as a rotor core. As a result, a particularly strong, mechanical fixation of the respective permanent magnet 10a-d on the carrier can be ensured. In particular, the respective permanent magnet 10a-d can be mechanically connected to the carrier in a form-fitting manner by means of the respective form-fitting element 24, 26 or 28, as a result of which particularly high forces or torques can be transmitted. Also the in 11 The trapezoidal shape shown of the base body 12 and in particular of the finished permanent magnet 10a-d enables a particularly advantageous, form-fitting attachment of the respective permanent magnet 10a-d to the carrier.

14 shows the base body 12 according to the fifth embodiment in a further schematic front view. In 14 the cutting beam is denoted by 30 . At the in 14 shown embodiment, the cutting jet 30 is a water jet. It can be seen that the cutting jet 30 or its jet direction encloses an angle β with the vertical V, which is different from 0° and from 180° and is in particular smaller than 90°. The base body 12 is acted upon by the cutting jet 30 at the angle β. It can be seen that the cutting jet 30 or its jet direction encloses a further angle δ with a surface 20 of the base body 12, the surface 20 of which is acted upon by the cutting jet 30, the angle β and the angle δ totaling 90°. The angles β and δ can be the same size or different from each other. This produces the trapezoidal shape of the base body 12 and thus of the permanent magnet 10a-d. In particular, due to the trapezoidal shape, it is possible to mechanically attach the permanent magnet 10a-d to the carrier in a form-fitting manner.

reference list

10a-d

permanent magnet

12

body

14a-d

recess

16a-d

subarea

18

another section

20

surface

21

die

22

opening

24

interlocking element

26

interlocking element

28

interlocking element

30

cutting jet

K

edge

L1

length range

A1

Top view

A2

side view

S1

first step

S2

second step

S2.1

substep

S2.2

substep

S2.3

substep

S3

Third step

V

vertical

W

wall area

a

angle

β

angle

δ

angle

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 10027086 A1 [0002]
• DE 10157433 A1 [0002]
• WO 03074229 A1 [0002]
• DE 102017200142 A1 [0002]

Claims (10)

Method for producing at least one permanent magnet (10a-d) for an electrical machine, with the steps: - producing a permanent magnetic base body (12) by compression molding or extrusion; - Separating a first portion (16a-d) of the base body (12) from at least a second portion (18) of the base body by a cutting process, the at least one permanent magnet (10a-d) being provided by the first portion (16a-d). ; and - Providing the at least one permanent magnet (10a-d) with a recess (14a-d) by the cutting process. procedure after claim 1 , characterized in that jet cutting, in particular water jet cutting, is used as the cutting method. procedure after claim 1 or 2 , characterized in that the separation of the first partial area (16a-d) from the second partial area (18) and the provision of the at least one permanent magnet (10a-d) with the recess (14a-d) are carried out in one go. Method according to one of the preceding claims, characterized in that the recess (14a-d) is produced as a blind hole or as a through opening. Method according to one of the preceding claims, characterized in that the recess (14a-d) runs in an arc, in particular in a meandering shape. Method according to one of the preceding claims, characterized in that the at least one permanent magnet (10a-d) is produced essentially triangular. Method according to one of the preceding claims, characterized in that the base body (12) is produced as a cuboid or trapezoidal. Method according to one of the preceding claims, characterized in that at least one form-fitting element (24, 26, 28) of the at least one permanent magnet (10a-d) is produced, which by means of the form-fitting element (24, 26, 28) is form-fitting to a carrier of the electrical machine is connectable. Permanent magnet (10a-d) for an electrical machine, wherein the permanent magnet (10a-d) is produced by means of a method according to one of the preceding claims. Use of a permanent magnet (10a-d) after claim 9 for an axial flow machine.

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